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United States Department of Agriculture

Agricultural Research Service

Title: A Key and Compendium to the Species of the Genus Merlinius Siddiqi, 1970, with Description of One New Species Parasitizing Date Palm

item Handoo, Zafar
item Islam, Shamsul - UNIV KARACHI, PAKISTAN

Submitted to: Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 16, 2007
Publication Date: April 1, 2007
Citation: Handoo, Z.A., Khan, A., Islam, S. 2007. A key and compendium to the species of the genus merlinius siddiqi, 1970, with description of one new species parasitizing date palm. Nematology. 9(2):251-260.

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that cause an estimated crop loss of 10 billion dollars each year in the United States. Stunt nematodes (Merlinius spp.) are an important group that feeds on the roots of many kinds of plants worldwide. One problem with determining the extent of stunt nematode damage is that the stunt nematodes present in an area can be identified only with extreme difficulty. Therefore, specimens or pertinent literature of all described stunt nematode species were examined and evaluated in the present study. A new diagnostic aid or identification key of all these species was prepared, and a compendium providing the most important diagnostic characters of each species was developed as a useful supplement to the key. The identification key and compendium are significant because they provide the only accurate, all-inclusive guide to stunt nematode identification. This research will be used by scientists, action agencies and extension agencies involved in nematode research and control.

Technical Abstract: An identification key to 32 valid species of stunt nematodes (Merlinius spp.) is given. A compendium of the most important diagnostic characters for use in identification of species is included as a practical alternative and supplement to the key. The diagnosis of Merlinius is emended, and a list of all the valid species of the genus is given. The characters most useful for separating species include body and stylet lengths, shape of head, tail and tail terminus, number of head and tail annules, position of vulva (V%), and T/ABW ratio in females. Also useful are length and shape of spicules and gubernacula in males. A new stunt nematode, Merlinius khuzdarensis n. sp., is described, photographed and illustrated and was found around the soil and roots of date palm (Phoenix dactylifera L.) from Khuzdar, Baluchistan Province, Pakistan. This new species resembles M. bavaricus, M. communicus, M. bilqeesae and M. montanus, but differs from these species by the following: body and stylet length, shape of head, tail and tail terminus, number of head and tail annules, position of phasmids and by their vastly different habitat. Because this species is limited in distribution, its economic importance in date palm and other cultivated crops within the region is not known.

Last Modified: 4/18/2015
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